Composite bearing inserts for total knee joints

Abstract

A composite bearing insert for a total knee joint or a unicondylar knee joint which minimizes or eliminates the production of wear debris resulting from relative motion at the interface between the endoskeleton and a tibial tray of a knee joint prosthesis. The composite bearing insert includes an endoskeleton and a polymer portion which is preferably molded into and locked within the endoskeleton. The endoskeleton is configured to be locked to a tibial component, such as a tibial tray or keel. The modularity of the assembly facilitates the interchangeability of various composite bearing inserts with various tibial components.

What is claimed is:  
     
       1. A modular composite bearing assembly for a knee joint, comprising: 
       a metal tibial element and a composite bearing insert structure attached to the metal tibial element, said composite bearing insert structure including a polymeric bearing component interlocked with a metal endoskeletal component, wherein said endoskeletal component is interlocked with said metal tibial element to prevent relative movement therebetween, and wherein said polymeric bearing component is configured to operatively engage a femoral component.  
     
     
       2. The composite bearing insert of  claim 1  wherein at least a portion of said endoskeletal component is shaped to securely interlock with said polymeric bearing insert. 
     
     
       3. The composite bearing insert of  claim 1  wherein said polymeric bearing component is made from polyethylene. 
     
     
       4. The composite bearing insert of  claim 1  wherein said endoskeletal component is made of a material selected from the group consisting of titanium, titanium alloy, cobalt-chrome alloy ceramic, biocompatible composite, polymer, and steel alloy. 
     
     
       5. The composite bearing insert of  claim 1  wherein said femoral component includes a plurality of condyles, and wherein said polymeric bearing component is configured to operatively engage said condyles. 
     
     
       6. The composite bearing insert of  claim 1  wherein said metal tibial element is adapted for fixation to a surgically prepared tibia using a technique selected from the group consisting of biologic fixation, mechanical fixation, and grouting fixation. 
     
     
       7. The composite bearing insert of  claim 1  wherein said polymeric bearing insert is interlocked with said metal endoskeletal component through an interlocking structure selected from the group consisting of a mechanical interlock, a chemical interlock, and an adhesive bond. 
     
     
       8. The composite bearing insert of  claim 1  wherein said polymeric bearing component is a compression molded polymeric bearing component. 
     
     
       9. The composite bearing insert of  claim 1  wherein said endoskeletal component and said tibial element are interlocked through a mechanism selected from the group consisting of a taper lock, a screw and a pin. 
     
     
       10. The composite bearing insert of  claim 1  wherein said tibial element is a tibial tray. 
     
     
       11. The composite bearing element of  claim 1  wherein said tibial element includes a tibial keel. 
     
     
       12. The composite bearing insert of  claim 1  wherein said composite bearing component is a composite bearing insert. 
     
     
       13. A method of constructing a modular composite bearing assembly for a knee joint, comprising: 
       constructing a metal tibial component;  
       constructing a metal endoskeleton component;  
       molding a polymeric bearing component to interlock the polymeric bearing component to the metal endoskeleton component to form a composite bearing component; and  
       interlocking the composite bearing component to said tibial component to prevent relative movement therebetween.  
     
     
       14. The method of  claim 13  wherein said tibial component is a tibial tray. 
     
     
       15. The composite bearing element of  claim 13  wherein said tibial element includes a tibial keel. 
     
     
       16. The method of  claim 13  wherein said composite bearing component is interlocked with said tibial component such that said composite bearing component contacts said tibial component only though metal to metal contact. 
     
     
       17. The method of  claim 13  wherein wherein said composite bearing component is interlocked with said tibial component through at least one of: screw fixation and an interlocking dovetail. 
     
     
       18. The method of  claim 13  wherein said polymeric bearing component is interlocked with a metal tibial component through at least one of: screw fixation and an interlocking dovetail. 
     
     
       19. A modular composite bearing assembly for a knee joint, comprising: 
       metal tibial element means and composite bearing insert structure means attached to the metal tibial element means, said composite bearing insert structure means including polymeric bearing component means interlocked with metal endoskeletal component means, wherein said endoskeletal component means is interlocked with said metal tibial element means to prevent relative movement therebetween, wherein said polymeric bearing component means is configured to operatively engage a femoral component, and wherein said modular composite bearing assembly is configured for attachment to the tibia of a patient.